New study highlights misunderstanding surrounding risks and benefits of tamoxifen

03/18/04

Use of tamoxifen by high risk women is low due to both failure of doctors to offer it and patients' refusal to accept it, according to the results of a new study led by researchers at Northwestern Memorial Hospital. While tamoxifen chemoprevention has been shown to reduce the occurrence of breast cancer by nearly 50 percent in women with elevated risk, this study shows that the drug's risks and benefits aren't always appropriately evaluated when determining who should take it.

The study, which will be published March 22, 2004 in the online edition of CANCER, is the largest to date to review use of the drug in risk-eligible women.

"The study shows that doctors tend to offer tamoxifen to women who will reap the greatest benefit from the drug due to risk caused by certain types of benign breast disease and to those at lower risk of severe side effects. That makes sense," explains Monica Morrow, M.D., the study's lead author and director of breast surgery at Northwestern Memorial Hospital. "What doesn't make sense is that women significantly less likely to have side effects, such as premenopausal women and those without a uterus, did not accept tamoxifen more frequently than other groups." Dr. Morrow is also a professor of surgery at Northwestern University's Feinberg School of Medicine.

"There clearly is a lot of confusion among women about the risks and benefits of tamoxifen chemoprevention," continues Dr. Morrow. "Our findings indicate a great deal of misunderstanding about tamoxifen's risks and benefits among women, probably due to all the negative press it has gotten over the years. They also indicate that we need better educational strategies to help women make this decision."

Study researchers analyzed data from 219 women with increased breast cancer risk to identify clinical factors that would predict its use. Overall, only 63 percent of the women were offered tamoxifen and only 26 percent accepted. The authors conclude, "Our findings indicate that both physician practice and the attitudes of at risk women are responsible for low rates of tamoxifen usage."

The United States Food and Drug Administration approved tamoxifen in 1998 for breast cancer risk reduction in women with elevated breast cancer risk. The worldwide data showed an average 38 percent risk reduction in breast cancer for all risk-eligible women, although the largest U.S. trial showed a 49 percent reduction. Women with atypical hyperplasia (AH) or lobular carcinoma in situ (LCIS) derived the greatest benefit – e.g., an absolute risk reduction of 86 percent for women with AH in one study. Approximately 2.4 million women are estimated to be eligible to benefit from tamoxifen.

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By John M. Grohol, Psy.D. on
21 Feb 2009
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